<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  </head>
  <body>
    <!-- font-size:2px -->
    <h1 id="app">h1 element</h1>

    <h2>h2 element</h2>
    <script src="1.js"></script>
  </body>
</html>
